The Chemical Entities of Biological Interest (ChEBI) ontology is downloaded weekly from EMBL-EBI at http://www.ebi.ac.uk/chebi/. The data is made available under the Creative Commons License (CC BY 3.0, http://creativecommons.org/licenses/by/3.0/). For more information see: Degtyarenko et al. (2008) ChEBI: a database and ontology for chemical entities of biological interest. Nucleic Acids Res. 36, D344–D350.
Phosphane (PH3) and compounds derived from it by substituting one, two or three hydrogen atoms by hydrocarbyl groups: RPH2, R2PH, R3P (R =/= H) are called primary, secondary and tertiary phosphines, respectively. A specific phosphine is preferably named as a substituted phosphane.